Solar Electricity and the Environment

Emissions and the environmental impact of power generation is back in the spotlight, thanks to the COP21 World Climate Summit held in Paris during December 2015. In order to achieve the targets set by the agreement, there has to be a big shift away from traditional power generation towards greener energy production.

No power generation technology is entirely environmentally friendly. Hydro-electric power stations have an impact on water courses and impacts local wildlife. Wind turbines account for a number of bird deaths every year. Building hydro, wind or solar equipment also has a carbon footprint that has to be taken into account. Yet this carbon impact is a tiny fraction of the carbon footprint associated with more traditional power generation technologies.

Once installed, a solar electric system is a low-carbon electricity generator. The sunlight is free and the system maintenance is extremely low. There is a carbon footprint associated with the manufacture of solar panels, and in the past this footprint has been quite high, mainly due to the relatively small volumes of panels being manufactured and the chemicals required for the ‘doping’ of the silicon in the panels.

Thanks to improved manufacturing techniques and higher volumes, the carbon footprint of solar panels is now much lower. You can typically offset the carbon footprint of building the solar panels by the energy generated within 2–3 years, and some of the very latest amorphous thin-film solar panels can recoup their carbon footprint in as little as six months.

Therefore, a solar electric system that runs as a complete stand-alone system can reduce your carbon footprint, compared to taking the same power from the grid.

In general, the same is now true of grid-tie solar. In the past, the power companies have struggled to integrate renewable energy into the mix of power generation sources. This has meant that whilst the energy produced by solar panels was non-polluting, it did not necessarily mean that there was an equivalent drop in carbon production at a coal or gas-fired power station.

However, over the past few years, power companies have become far better at predicting weather conditions in advance and tuning the general mix of power generators to take advantage of renewable energy sources. This has ensured a genuine carbon reduction in our energy mix.

Of course, the sunnier the climate, the bigger benefit a solar energy system has in reducing the carbon footprint. In a hot, sunny region, peak energy consumption tends to occur on sunny days as people try to keep cool with air conditioning. In this scenario, peak electricity demand occurs at the same time as peak energy production from a solar array, and a grid-tie solar system can be a perfect fit.

If you live in a cooler climate with less sunshine, peak energy demand often occurs in the evening, when solar energy production is dropping. This does not negate the carbon benefit from installing solar, but if you want to maximize the carbon benefit of a solar energy system, you should try to achieve the following:

• Use the power you generate for yourself
• Use solar energy for high load applications such as clothes washing
• Reduce your own power consumption from the grid during times of peak demand
• Store some of the excess solar energy production using batteries and use it in the evening

Environmental efficiency: comparing supply and demand

There is an online calculator to map your electricity usage over a period of a year and compare it with the amount of sunlight available. Designed specifically for grid-tie, this calculator shows how close a fit solar energy is in terms of supply and demand.

Whilst this online calculator is no substitute for a detailed electrical usage survey and research into the exact source of the electricity supplied to you at your location, it will give you a good indication of the likely environmental performance of a solar energy system.

To use this online calculator, collate information about your electricity usage for each month of the year. You will usually find this information on your electricity bill or by accessing your electricity account online. Then visit http://www.SolarElectricityHandbook.com, follow the links to the Grid-Tie Solar Calculator in the Online Calculators section.

 

Greedy for Power

 

We have a problem in the developed world. We’re greedy for more and more power. We can never have enough. We take energy for granted. Plug a hair dryer or a kettle into a socket and switch it on and it just works. Cold? Turn up the thermostat or adjust the timer on the central heating and we’re warm in minutes. We don’t have to think about the amount of energy we want to use, it is there for us whenever we want it at the flick of a switch.

It’s the same with our cars. Get in, fire up the engine and you have an enormous amount of power under your right foot. Even a small family car has an engine that could produce enough power to provide electricity for one hundred houses or more.

What has made all this possible is fossil fuel: oil, gas and coal. These fuels are amazing. They pack a huge amount of energy in a very compact form. The amount of energy in one litre of petrol (gasoline) is around the same as the energy stored in 250kg (550 pounds) of batteries. We’ve become pretty good at transporting fossil fuels around the world and we use them when we need them. As a form of usable energy, fossil fuels are pretty much unbeatable.

Of course, there are problems with fossil fuels. Supply and demand, climate change, the occasional war… I’m not going to list them all here. But the issue is this: we have become addicted to oil and the benefits it gives us. We don’t want to lose those benefits. Whatever we use to replace fossil fuels, the public demands that we should be able to carry on doing the same things we currently do.

And that is a big mountain to climb. Renewable energies are very good at producing smaller amounts of energy, but harnessing it on a utility scale is a huge undertaking. A single solar photovoltaic panel will produce, at most, around 300 watts of power: enough to watch TV, perhaps, but only a fifth of the power required to run a washing machine. Wind turbines can produce far more, but in comparison to the power output of a conventional power station, the numbers are tiny.

One of the biggest issues with most sources of renewable power is that we get the power when nature dictates. Solar power relies on sunlight, wind turbines rely on wind. Even hydro-power, which is one of the more reliable and controllable sources of renewable energy, ebbs and flows with the seasons.

That simply does not fit in with our demands for energy when we want it. It means that renewable energy technologies have to be supplemented with other forms of energy production. Here in the UK, a huge wind turbine building scheme now means that it is quite common for wind power to supply 20% or more of our nation’s electricity at any time.  Yet on a calm day, the power output from wind turbines can be as low as 1% of our demand. The supply of this energy can fluctuate in just a few hours, making it difficult to manage supply against demand.

Traditional power stations struggle to manage this fluctuation. Coal and nuclear power stations are at their most efficient when running at a constant rate. In the UK, gas-turbine power stations are being used as load-balancers, increasing production when wind energy is low and reducing it when wind energy is higher.

Technology is evolving and we are resolving the issues. Tidal and wave energy, for example, has the potential to provide large quantities of reliable around-the-clock energy, whilst the development of stored solar thermal technologies in Spain demonstrates a way of providing a reliable 24-hour energy source from the sun. Right now in Sweden, I’m working on a wind farm project working with hydro-electricity to handle the peaks and troughs. It has the potential to eradicate the need for fossil fuels for electricity production in Sweden within the next four years.

We are getting closer. We have the technology and the ability to generate an abundance of electricity from renewable sources. We will be able to do it cost effectively and we will be able to have energy when we want it, not when nature decides to give it to us. We don’t have all of the answers yet, but we will do.

Will fossil fuels be redundant within my lifetime? Probably not. But at least we will have broken our addiction to oil and have a greener and cleaner source of energy, provided by nature, which will never run out.

 

Written by Michael Boxwell, bestselling author of the Solar Electricity Handbook.