Batteries for Solar Panels
We’ve had solar panels for a good while now and many of us have them installed on our roofs. One of the major hurdles to energy independence, however, has so far eluded us – namely how to store that valuable electricity on site for use locally when the sun isn’t shining.
This development has the potential to make each home energy independent and to greatly reduce our reliance on large utility companies and the National Grid. It’s one of the big innovations of the last few years and it is beginning to gather pace.
In short, solar power technology for solar panels could revolutionise the way we use energy.
The good news is that in recent years the solar storage industry has started to move forward and with products from companies like Tesla and Samsung the future is starting to look much brighter. Many suppliers and installers are now incorporating combined solar and storage when they visit a customer. These are undoubtedly relatively early days but this new technology could allow the solar industry to thrive without the need for subsidies paid by us through our utility bills.
How Storage Works at the Moment
Solar panels fit on your roof and attract the energy from the sun. They use solar cells to convert this energy to electricity and currently provide power for homes and businesses across the UK. At the moment, this electricity is produced mainly when the sun is shining onto the panels and is then sent to the National Grid. Homes and businesses with solar panels basically sell their electricity to the utility companies and receive a set amount through the Feed in Tariff in return – basically the Grid acts as the storage mechanism ensuring we have power 24/7.
Why We Need Storage
When solar first started to become a possibility in the early 80s and 90s, the idea of power storage and how to achieve it locally was at the forefront of developers’ minds. Eventually, the solution to pour the power back into the grid took precedence and actually led many people to decide to have panels installed on their roofs. Not only that, many businesses and organisations began to see it as a way of boosting their green credentials and reducing their energy bills. All this, however, depended on a certain amount of subsidy with the utility companies paying for the electricity produced. The problem is this is benefit for having them installed is about to be dramatically reduced by the Government.
There has always been a desire to create a system that is actually independent of the grid and storage development is now starting to come full circle again with efficient batteries that can be placed in homes or businesses, making them energy sufficient without relying on the National Grid. In other words, the creation of a workable storage solution should allow people to use the electricity they produce 24/7, bypassing the need to pay utility companies.
That’s all in theory. In practice, there are some hurdles to still overcome.
The Problem With Storing Your Own Electricity
For a long time the problems with solar power storage units were their efficiency, how long they were going to last before they needed replacing and the ongoing cost compared to accessing the National Grid. In the initial stages, the prospect of a good return on investment was limited but there seems to have been a real sea change in the last two years which means that prices are set to come down and the quality of product is beginning to improve. The initial costing for the much vaunted Tesla battery was around £10,000 but has come down dramatically to £2,000 in a pretty short space of time.
Many companies are starting to position themselves now as suppliers and installers of solar storage units that could literally change the way we look at power supplies and our own, individual energy independence, both at home and in the commercial sector.
How Solar Storage Works
Systems with the ability to store their own electricity for solar have three vital components:
- Solar panels that collect the energy from the sun and convert it to DC electricity.
- A battery or series of batteries that store the electricity produced.
- An inverter that converts DC current to AC so that it can be used around the home.
The main point about in-house batteries is that they need to store enough electricity to get a home or business through that period when the solar panels are practically dormant. The average home uses in the region of 5,000 kW/h per year or 13 to 14 kW/h per day and much of this is either early in the morning or in the evening (assuming the house is empty during the day). How much you use will define the number of batteries you have installed and the overall cost if you want to make sure you are covered in times of greatest need.
One of the prime movers in the solar power storage market has been Tesla, perhaps better known for their work on hybrid and electric cars to date. They have used the technology they have developed in the car manufacturing market to produce a lithium ion battery which they call Powerwall.
They currently produce a 7 kW daily and 10 kW weekly battery that is easy to install and provides power for when your solar panels are not producing electricity. These are guaranteed for 10 years and can provide the energy needed for a normal working home. Additional batteries can be added for those with higher electricity needs. The Powerwall also contains the inverter to convert DC current to AC.
Weighing about the same as an average person, the Tesla Powerwall is certainly a large piece of kit and costs between £2,000 and £2,500 (not including installation and install prices vary wildly). Tesla began shipping their 7 kW version of the battery to the UK in September 2015. Much depends on whether the market starts to take up this kind of technology in large numbers and that is going to depend on a number of factors, including overall cost, efficiency and longevity.
Samsung SDI Batteries and Other Providers
Tesla are not the only solar power storage units that are starting to make their way onto the market. Samsung SDI have produced 5.5 kW and 8 kW versions which were unveiled at an event in Munich in 2015. These have a warranty for five years and performance is guaranteed for 10. Their Residential ESS system is said to be ideal for homes but they also produce much larger batteries up to utility level and will no doubt be one of the big players on the market over the next few years. Players such as LG Chem and even Mercedes Benz have also entered the market and their presence is starting to drive the prices down for solar storage, giving consumers a greater degree of choice.
Can You Go Off Grid?
This is the big challenge for solar storage – whether we can cut off our supply from the National Grid and actually be electricity independent from the utility companies. The trouble is that, whilst the market is beginning to expand and the technology is developing more rapidly, there is always the worry of what happens when your capacity over-reaches or the battery develops a fault. If you have disconnected yourself from the mains supply then what do you do without any electricity at all? Then there is the cost of maintaining and replacing batteries and the long term issues of basically being your own, independent energy manufacturer.
The truth is it may be a little too soon for some people to opt for the installation of solar storage batteries – it will probably take more time for consumers to adopt them on a large scale. For businesses with larger systems that need someone onsite to maintain the power it can add even more costs – that of employing people to do the job and the problem if power is suddenly taken away and the consequent loss of sales and revenue.
Storage That’s Not Just for Solar
The truth is that a battery storage system can be used for any renewable system, including hydroelectric and wind turbines. The unique position of solar is that it only produces sufficient electricity when the sun is shining but storage could also be used for other energy systems to help with times when there is a strain on capacity; for instance, when a factory has a large order to complete.
The Future of Solar Energy Storage
Intelligent storage may well be the future of greater energy independence, at least in the shorter term. Many developers are now beginning to produce digital technologies that monitor energy usage and combine that with power production to make sure that electricity is available as and when needed. For instance, in an average home where everyone is working, more power is used in the morning and in the evening than during the day. Businesses will have other peak demands that will benefit from a more controlled energy storage system. Batteries with a much longer lifespan and better capacity will also help make the break from a total reliance on the National Grid and lead us to more independent electricity production.
In the immediate future it may well be the case that we will need a hybrid mechanism that stores electricity but also has access to the National Grid. That will then reduce the amount of electricity that requires a payment to the utility companies but will also require the development of further technology. In the longer term, we may have a situation where localised energy storage will indeed mean that many of us can become independent of the National Grid.
The question will be how the installation is funded and whether universal access can be created which means we all benefit from clean energy that is homemade.
You can find local installers and suppliers of solar panels and storage systems on our database.