We here at Northmore Gordon, are very optimistic about the future. Some think that moving towards a carbon-neutral economy is too hard, too expensive and will take too long.
Moving to a carbon-neutral way of life is challenging, but completely do-able. Whatever technological, process, or economic challenges are in place, we can work together to find solutions.
The technology that we have is constantly changing, and who knows that amazing invention will be developed next that will have just as a big (if not bigger) impact as solar panels?
We must all take a multi-faceted approach to the challenge, and think outside the box to find novel solutions, and/or novel applications of old solutions.
How to get the most out of your solar power?
If your facility has facility has solar panels, or you are thinking of getting solar panels, or both, and your system is likely to generate more power than you use, especially in summer, here are some strategies on how to make the most of the power from your solar system.
Solar Power Variability
The nature of solar panels is that its output is highly variable with with seasons. The output in summer can be approximately three times of the output in winter.
Once upon a time there was a legislated minimum feed-in tariff from solar panels, the tariff was very generous, and had the desired effective of increasing solar installation domestically around Australia.
The feed-in tariff now is small comparatively, and typically ranges 10 – 15 cents per kilo-Watt-hour depending on your retailer, location, time of day, and contract.
Are we better off using excess power on site?
Depending on the cost of your facility’s electricity – you may well be better off, economically, to use as much electricity as possible during high-output times.
How to use more power smartly?
One of the most obvious ways to store excess electricity for later use is batteries. The downside of course is that they are somewhat expensive at the moment.
There are other ways to store excess power for use later:
- ice storage: existing refrigeration compressors are used to generate ice in a dedicated unit during times of free or no-cost electricity. The ice can also be used to assist with site chilling or cooling requirements during times of high-cost electricity. The ice storage unit can also act as a buffer tank for times with there are spikes in refrigeration demand.
- Example: a diary facility uses their excess solar panel power to generate ice during the peak of the day, that stored ice is then used later in the day with little or no solar power to cool deliveries of milk
- hot water storage: use existing solar thermal or heat pump units to generate excess hot water, and store for later use. Depending on the storage tank, the temperature of the stored hot water can be higher to enable more energy storage – mixing with cold water at time of use may be appropriate. Just make sure the tank is very well insulated to minimise heat loss to the environment.
- Example: a dairy farmer uses the excess solar power to generate hot water using their heat pump units during the middle of the day; in the late afternoon after milking, the hot water is used to clean and sterilise all milking equipment
- phase change materials (PCM): A PCM is a material that changes phase (e.g. solid to liquid) at a certain temperature e.g. ice to water at 0°C; other materials are available that change phase between 0 – 10°C. Due to the phase change, a large amount of energy can be stored in the PCM. If there is cheap or excess electricity supply, then room set points can be changed, with the PCM storing the thermal energy as it freezes.
- hydrogen: hydrogen has been making a quiet come-back with companies developing (relatively) simple plug-and-play units where hydrogen is generated (via electrolysis) using excess electricity, stored, and then converted back to electricity via fuel cells. It is, at the moment, very expensive. However, hydrogen is a highly viable carbon-neutral fuel for buses, trucks and large transport vehicles.
Load shifting – which is changing the times when items are used when electricity is cheapest – is an old concept. Historically, when off-peak electricity prices are lower than peak prices, then operating equipment during off-peak where possible, could reduce your overall power bill.
With excess solar power, the concept is the same, but the equipment now needs to be operated during middle of the day rather than at night.
The limitation, of course, is the process flexibility to change equipment operating hours.
Example: A water treatment plant that needs to pump water from location A to B for several hours a day on a daily basis can schedule their pumping hours to best suit their solar panel power output, and/or times of off-peak power.