At Joju Solar, one of the most common questions we are asked is “what is the most efficient solar panel?” Here’s our guide to the best of the best.
By the end of 2018, it is estimated that there will be around 200,000 plug-in hybrid (PHEV) or pure electric (EV) vehicles on the road in the UK. READ MORE
Choosing the right electricity tariff for you can be pretty confusing. READ MORE
Sales of electric vehicles (EV) and plug-in hybrids (PHEV) in the UK rose by 27% in 2017, year on year, and the latest figures, released in April 2018, show that around 146,000 plug-in vehicles are currently driving around on our roads.READ MORE
In this week’s blog, our Technical Director, Dr Chris Jardine, meets philosopher and author, Roman Krznaric. Together, they discuss the importance of time horizons when thinking about sustainability. READ MORE
Internal combustion engines, for all their flaws, are design classics. Why let them go to waste? In this guest blog, Steve Drummond from Electrogenic explains why you should consider converting classic cars to electric.
We’re currently building a 2MW community energy scheme with a Welsh community energy group called Awel Amen Tawe. Their Egni Coop is working with Newport Council to install solar on their schools and other public buildings such as the velodrome. Dan McCallum from Egni Coop, has written this rather excellent blog piece, looking at the finer details of the project panning and installation process.
As a solar engineer, it’s my job to understand the movement of the sun across the sky throughout the year. However, a technical understanding of solar movement often feels at odds with my appreciation of the world around me. That confusion comes from our cultural perceptions of the seasons, and their definitions. So, when exactly do spring, summer, autumn and winter start and end?
From a solar perspective, we can look at the movement of the sun across the sky. We know that at the summer solstice, June 21st , that the sun reaches it’s highest point in the sky, and that our days are longest. Similarly, at the winter solstice (December 21st), the midday sun is at its lowest point in the sky, and the days are at their shortest.
Midway between the two solstices lie the spring (20th March) and autumn (22nd September) equinoxes. These dates don’t get as much attention as the solstices, but consider this – on the date of the equinoxes, everywhere on the planet receives exactly 12 hours of daylight. It doesn’t matter if you’re in Aberdeen or Abu Dhabi, on these days, everyone is equal.
Solar energy varies from solstice to solstice
These definitions imply that the solstices and equinoxes are the midpoints of the seasons. It’s always annoyed me when people talk about the summer solstice as the first day of summer – from a solar energy perspective it’s the middle of summer! Crazy fools!
It’s something our pagan ancestors understood very well. We know that they understood the passage of the sun across the sky in intricate detail – look how Stonehenge aligns with the summer solstice, and the entrance passageway to Newgrange in Ireland aligns with the winter solstice. The four points between the equinoxes and solstices were marked with festivals, each denoting the beginning of a season. Beltane (May 1st) marked the start of summer, and Samhain (31st October) the start of winter. These two, in particular live on in modern times. May 1st is still celebrated as the start of summer. In Oxford, for example, 1000’s of revellers gather at dawn to mark the start of summer, with choir singing, morris dancers, bands, and (lets be frank here) the chance to go to the pub at 6am. Simialrly, Samhain marked the start of winter, and now lives on as Halloween.
Similarly, the start of spring was celebrated on 1st Februray (Imbolc) and the start of autumn (Lughnasadh, or Lammas) on the 1st of August.
And this is where the whole thing falls apart for me. Really? Autumn starts on the 1st August? A week ago we had the hottest day the UK has ever seen, and today it’s meant to be the start of autumn? Are you kidding me?
The above description of the seasons doesn’t even tally with what we were taught at school. Back then, I was told:
So what’s the difference? It comes about because our perception of the seasons is more about heat than light. There is a lag between the times of maximum sunlight and the times of maximum heat, as it takes time for the land and oceans to warm up. This means what we feel (temperature) is out of phase with what we see (sunlight). If we consider the lag between sunlight and heat to be 1 month, that shifts the solar definition of the seasons in line with what we were taught at school. If we consider the time lag to be longer at 6.5 weeks, then the crazy fools who say the summer solstice is the start of summer, would actually be correct.
Temperature in London, UK peaks after the summer solstice (from www.yr.no)
Now here’s a thought. What if there aren’t 4 seasons throughout the year? In north European climates, the year can actually be divided into 6 seasons of 2 months each. These are based on ecology – the observed plant and animal behaviours that are seen exclusively in these seasons. They are defined as:
For me, this seems a much better description of the passing of the year. The ‘extra’ seasons of pre-spring and harvest capture those time of year perfectly, autumn is reserved for just the period of falling leaves, and brilliantly, winter is only 2 months long.
So, as I write this on 1st August, welcome to the start of Serotinal! That sounds a bit of a clunky phrase – and it might take a while to catch on! But it doesn’t sound as weird as autumn starting, when its 25 degrees outside.
So, take a look around, observe your surroundings, and find which one of these three seasonal definitions suits you best.
Joju Solar will be exhibiting at Fully Charged LIVE again this year. The 3-day event will be held at Silverstone Race Track from Friday 7th – Sunday 9th June. The event is put on by Robert Llewellyn and the team behind the Fully Charged Youtube Channel, and will feature all the latest from the world of electric vehicles, and renewable technologies for the home.
We can safely say that last year’s event was by far the best trade event we’ve ever attended. The expected audience was well exceeded and 65% of those turned up within the first hour of the first day. When the doors opened at 10am, the surging crowds were more like a Black Friday sale than any renewable energy show we’d ever been to.
That’s our stall with the orange posters on the right hand side. We didn’t stop talking solar, battery storage and EVs all weekend!
This year’s event promises to be even better; the venue is now double the size and there will be a wider range of activities. The highlights include:
So grab your tickets and come and say hello! We’d love to talk to you about any new projects you might have, or simply catch up with our old friends and customers. Hope to see you there!
Back in the 1890’s a power station in central Oxford powered a local grid that ran the city. As demand for electrical power grew, many small local networks like this across the country were developed. However, by 1925, such an approach was seen as inefficient and fragmented, and major review was conducted by Lord Weir. The British Government created the Electricity (Supply) Act of 1926, which recommended that a “national gridiron” supply system be created. This was the formation of the National Grid as we know it, a back bone of high-voltage transmission lines feeding lower voltage local distribution networks. One outcome of this, however, was that it supported a model of large centralised electricity generation; many GW of coal, gas and nuclear plants supplying the bulk of our power.
Now, in 2019, the challenges are very different. With the need for rapid decarbonisation of electricity to mitigate climate change, not to mention the fact that renewables are now cost-competitive with traditional generation, we now have many smaller generators connected at the bottom of the electricity grid.
Which poses the question: is the old localised energy grid model a more appropriate way of managing our electricity system in the 21st Century? Has the wheel turned full circle?
This is what a major new project, Project LEO (Local Energy Oxfordshire), is looking to find out.
Project LEO is a £13.8m project over 3 years, run by a consortium of Scottish & Southern Electricity Networks, Open Utility (Piclo), EDF Energy R&D, Nuvvé, Low Carbon Hub, University of Oxford, Oxford City Council, and Oxfordshire County Council. The aim of the project, as the name would suggest, is to develop a local electricity market for Oxfordshire, that supplies its own needs, ensures reliable grid operation, and rewards generators a storage for the energy and flexibility they provide.
Why is this project being developed in Oxfordshire? Currently the grid in Oxfordshire is constrained, meaning it’s hard to connect more renewable energy projects to the grid; the grid is essentially full. There are two potential ways to solve this:
Put another way, lets imagine a new massive solar farm was connected to the grid. In summer the excess power would blow up the existing substations – no-one wants that! So the first option would be to build a new substation at considerable cost. The second option would be to find nearby users to take that excess power, which is likely to be considerably cheaper.
To facilitate this, Project LEO is developing a local energy marketplace, to control and manage the operation of the ‘assets’ in a smart local energy system. These assets might include hydro generation on the Thames which could be ramped up and down, or large heating systems such as the Bodleian book depository, which could be used flexibly according to available renewable power. It could also include smaller solar PV systems, batteries and smart EV charging.
And this is where Joju Solar comes in! We’re going to be working with our long-term community energy partner the Low Carbon Hub to deliver solar and storage projects that integrate with the Project LEO local energy marketplace. Lots of innovation will be required. For example, currently batteries charge from solar, and discharge to meet demand within the home. In future, batteries will still charge from solar, but might discharge when Oxfordshire needs it, rather than when your home needs it. This should reduce costs for everyone, and allow more renewables to be connected to the grid. However, it won’t be easy; devices will need the ability to ‘talk’ to the grid for them to be able to respond to the signals from the local market.
It’s a very exciting step for us – to go beyond simply installing generation and storage in people’s homes and businesses, and actually help create a local smart electricity grid. We can’t wait to get started.