Solar Panels, Battery Storage and a Heat Pump together
Towards the end of last year I told you about the technology we have had installed our the property to reduce our carbon footprint, including solar panels, a heat pump and electric car. Since then we have incorporated battery storage into our installation, which has been a real gamechanger for us. This morning I spoke at the Small Business Britain Sustainability Basics Course about this solar generation and storage set up designed to help us achieve the SME Net Zero Target in our business. Here is some of the background, plus how battery storage, solar panels and a heat pump together are working to reduce our energy costs and our carbon footprint.
Retrofitting an old shop - Background
Our family and our business occupy one building. Whilst living and working in the same property is not everybody's first choice, it is perfect for reducing your carbon footprint. That is because any positive change you make to your home reduces the carbon footprint of your business, and vice versa. You only have to invest once to benefit twice, you might say.
Our building is a 3 bedroomed house with well sized (another way of saying 'expensive to heat') rooms, a cellar and a loft, with an old shop on the front. It was built over 100 years ago and, broadly speaking, the building doesn't look vastly different to how it looked when it was new.
Needless to say therefore, everything has been retrofitted. Incidentally, as well as the major installations below which means we have battery storage, solar panels and a heat pump together, we are always making tweaks that further reduce our energy consumption in our business and our home. Many of them are not on the scale of what I'm about to describe. TP-Link Smart Plugs, LED lightbulbs and plug timer sockets have an important part to play in reducing our carbon footprint, and we use them all. As far as we're concerned, everything counts.
Installations Timeline
1. January 2013: Solar Panels installed (3.32 kW system, 13 x 255 watt panels)
2. June 2017: switched from petrol car to 100% electric (Nissan Leaf). Car charger fitted.
3. July 2021: Gas Combi boiler (no water tank to this point) removed. Mitsubishi Air Source Heat Pump installed to heat the building and the water, including a highly efficient and enormous Joule water tank.
4. August 2021: Gas supply and gas meter removed.
5. December 2021: Solar iBoost Water Heating Device fitted. This solar immersion controller sends excess solar to heat the water tank, maximising your solar panel investment. It needs a water tank to function which is why we could only have one at this stage.
6. December 2021: Battery storage pack fitted. The battery stores solar and grid energy to run the building.
How it all works together
The key to all this is leveraging the power of these devices working together. Whilst our cellar is rapidly becoming one big fuse board and parts of our loft look a bit like a flight deck, in reality we run most of these devices via apps on phones and iPads. This is what happens every day:
1. The Alpha Energy storage battery charges overnight on Economy 7 rates. Or rather, it does in the winter. As I write this it is almost April, and there is enough strength in the sun to charge the battery to 50% in an hour or so when we get up and the sun is shining. Within a month we will leave the sun to charge the battery completely. But in the depths of winter when we don't generate much solar power and the days are short, we would charge it up fully overnight. In other words, the extent to which we charge the battery from the grid is variable depending on the time of year.
2. The sun rises and and the solar panels generate electricity. Together with power from the battery, this will supply all the energy to our building. Whilst this is happening we are effectively off grid, and the power to run our home and our business is either from the energy stored in the battery or the sun - usually a combination of both. If however we use more than the battery and solar can provide because I forget and put various electrical appliances all on at the same time, then we will draw from the grid to top up to what is needed.
3. Because you never use energy consistently through the day, often there will be solar power left over. That surplus energy tops the battery back up to 100% through the day, as the battery discharges power to run the building.
4. When the battery is full, the iBoost kicks in to store any excess energy in the water tank, in the form of hot water.
5. Only when the battery is 100% full and the water tank is to temperature does any unused energy get exported to the grid. Our mission is always to minimise how much we export to the grid, particularly now that energy is so much more expensive than it was when we had the panels installed 10 years ago. The key therefore is that I don't put all our energy-sucking devices on at the same time, but rather stagger the usage of the washing machine, dishwasher etc to make the most of the solar we generate and avoid exporting anything if humanly possible. Incidentally that is the age old way of making the most of your solar batteries when you're out to work all day and have no storage batteries: having all your appliances on timers.
6. When needed, the heat pump is running quietly in the background keeping all the rooms at a constant 19 degree temperature during the day, and at around 17 degrees at night. Without getting into too much detail here, an air source heat pump is a completely different animal to a gas boiler. We would have been insane to leave a gas boiler on day and night. It would have cost the earth, in every sense. But I promise you that a heat pump isn't like that. We tested turning it on and off as it was needed when it was first installed (which was absolutely not what the installers advised us to do but we know everything, obviously) versus leaving it on all the time. Once the property is to temperature, running a heat pump all the time uses far less energy than turning it on and off when you think you need it. Keeping the building at a constant 19 or so degrees uses little energy, trying to heat it up from cold uses masses of energy because heat pumps are not like gas boilers, they are not designed to work that way. So during the winter months we leave it on. Anyway what all this means in practice was demonstrated yesterday, which was a Sunday. We were effectively off grid from 8am to 6pm because the sun was shining, the shop was shut and we weren't using much power in the house. And it is only March.
7. Evening comes and we run the house on the battery. Then if it's winter the battery charges up again overnight. If it's not, we set the battery to start recharging in the morning when we're generating.
Main Benefits of a Solar Set Up Like This
I can bore for England about how wonderful this set-up is. In the interests of brevity however, here are a few of the key benefits.
- A reduction in the costs of running our business, particularly in the summer. That said, we saved one third of our electricity consumption in February this year compared with last year, with no gas charges on top. Hence I can now confidently declare that you can generate solar power in England in the cooler months, and running a heat pump 24/7 in the colder months does not cost significantly more - if at all more - than heating your water and home with a gas boiler.
- A significantly reduced carbon footprint for the building. When you're trying to reduce your emissions, removing gas completely from the property is a big one. We also made a point of having our gas supply capped off and the meter removed, otherwise we would continue to incur an (ever increasing) daily standing charge even if we never use gas ever again. Who knew?
- Future proofed against rising energy costs. Once you've invested, the installation cost obviously remains the same regardless of what happens to energy prices. Service and maintenance costs for this equipment, based on our experience, are minimal.
- Reduced dependency on utility companies. Most batteries will switch into action in the event of a power cut, as ours does. Not all though, so do check if you're considering battery storage. This was an amazing benefit in the power cuts in England earlier this year. Our power was out for 6 hours but we were able to continue running the shop the whole time. Of course it didn't help us much when Royal Mail cancelled all their shop collections so the post didn't go anywhere... but it was still great to stay on top of orders and be able to communicate with customers.
- Periods of the year when it will cost just about nothing to run this building. We can already see that there will be times when we use just about no grid electricity at all. That may becoming interesting with our renewable energy supplier. They're already querying our consumption and haven't approved our bills for the last 2 months because I don't think they believe our readings. I have told them what we've done in this building (over and over), sent them photographs of everything (over and over) and still our bills sit 'in draft'. I'm assuming that, eventually, they will believe me.
When is a good time to install Solar Technology?
One of my favourite Chinese Proverbs is: When is the best time to plant a tree? 20 years ago. When is the second best time to plant a tree? Now.
This logic applies perfectly to installing solar technology in your property. Our solar panels are 10 years old. We probably paid more in 2013 for what is a relatively small installation, 3.32 KW, than we would today. But it had paid for itself in under 8 years. Meanwhile those panels are guaranteed for 25 years, so we have 15 more to go. Had we not started with the panels, we may never have started at all.
As always, big thanks to Ohm Energy who have worked patiently with us designing and developing this installation over the past 10 years. We couldn't have done it without them. If you're in shouting distance of Eastbourne where they are based, we would recommend them without hesitation.
So if you're contemplating getting started with solar technology, then our best advice is to just start with something. And with the well publicised and ever-increasing energy costs, that time is now.
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FURTHER READING
The Sustainable(ish) Living Guide, Small Changes that Make a Big Difference - Jen Gale
How to Avoid a Climate Disaster - Bill Gates
Ideas on Growing Your Business Sustainably - Wayne Toppen
Other Almost Off Grid Favourites
Solar Panels, Electric Cars and Heat Pumps - achieving net zero by 2030
Making Sloe Gin with Dried Sloes
Small Batch Dandelion Mead Recipe
Great article! Combining solar panels, battery storage, and a heat pump can create a highly efficient and sustainable energy system for homes and businesses. The solar panels generate electricity from sunlight, which can be stored in batteries for use during times of high demand or when sunlight is not available. The heat pump uses this stored energy to provide heating and cooling, further reducing the need for non-renewable sources of energy. This integrated system can result in significant cost savings, lower carbon emissions, and increased energy independence.
Hi, We have just had a heat pump system fitted under the ECO4 funding and have paid for one 4kw battery ourselves (and soon another battery). It took a while to get used to but one thing we have noticed is that the battery is always flat in the morning despite us turning off everything we can and sometimes when we watch the app (which is mesmerising ) we notice that the panels sometimes send power to the grid even when the battery is not full. I am presuming that the battery can only charge at a certain rate. I had not thought of charging the battery off the economy seven but as I said we are just getting used to the system. Our energy bills have been slashed by about 75%.
Very helpful many thanks
Hi John, from our experience your electrician is right. You would need a huge storage battery to run a heat pump. So we have never connected our heat pump to our battery storage. This is because we’ve become used to how a heat pump works, and how much energy it could take from your battery in the event of a power cut. When it’s really cold you are better off leaving your heat pump running day and night, or that’s how it works in this property. Even at current electricity rates, it doesn’t cost that much to run if you keep your property at a reasonable temperature all the time. When you try to heat a house from cold with a heat pump it costs a fortune. We learned this the hard way in our first winter! So when it’s a bit nippy in the evenings but not cold enough to have the pump going all the time, we light a fire. When the temperature comes down properly through the winter, we leave it running all the time and it just kicks in when the temperature drops below whatever we set it to, which is slightly warmer in the day (around 20) and slightly cooler at night (17-18) but we never let the house get cold. But if there’s a power cut in winter, we light the burner rather than having the pump connected to the battery, because it would drain the battery in minutes flat in the event of no mains power. We don’t have any of our kitchen appliances on the battery either, for the same reason. We basically have all lights, all our shop power socks and lights and a few random plug sockets around the house connected to the battery, so we can continue to run the shop if the power goes off during the day, and can see and run a few appliances at night if it happens at night. Yes that means cold water once the tank is empty, but I’d rather be able to see and run a few appliances than have hot water. Usually a power cut is brief around here but, in the event of it going on for a couple of days, we don’t want to drain our battery in 2 hours and then have no power, it kind of defeats the point of having the battery back up in the first place for us. Hope this helps!
This is all well and good but!you don’t say how much all of this as cost?and did you get any help with paying for it?I am wanting to do this heat pumps and solar panels and comming off grid?but I am not clever enough to sort this out and so I need the right help and a full package deal so I can see what its going to cost?I have noticed that they all quote stupid prices just to rope you in ,and what was£4K jumps very quickly to £15K!they start saying labour,scaffolding, inverters battery’s?I need a full package deal one price?