Solar Power in New Zealand Schools

One of the questions that comes up when researching solar power is that as all of the generation comes during daylight hours it is off-peak and less useful.

In Australia daytime energy use is actually peak because of air conditioning and I suspect the changing work patterns such as significant numbers of people working from home at least part time.

In New Zealand where summer time temperatures are lower than in Australia we don’t seem to have gone for air conditioning on quite the same scale. Although that looks to be changing with prices coming down for air conditioning systems and increased awareness from advertising by suppliers in that sector.

Earlier this month I was looking at some of the numbers on solar generation and by the time we convert kw to MW and then to GW the numbers get a bit abstract. To put solar powered homes into perspective I found this over on the EECA website.

“On average, New Zealand has about 2000 hours of bright sunshine each year. In energy terms, New Zealand’s solar energy resource is about 4 kWh/m2 per day. To put that in perspective, if every New Zealand home had a 3kW photovoltaic (solar) panel array, they would collectively generate enough power in a year to satisfy over a quarter of New Zealand’s annual residential electricity needs.”

That would be impressive and add a degree of resilience to the NZ energy system plus position us for powering up electric cars as that technology improves over the next decade or two.

So if we were looking at places to install roof top solar power generation in NZ where would be great?

My guess is that business premises and especially schools other educational places which use power during the day in New Zealand would be great places to add PV panels. Add to that in the case of most schools they are relatively empty for 2 months of the year so may be able to generate a small surplus if the systems were large enough.

If I was looking for a win/win policy for schools I would encourage all of them to setup solar PV arrays. Some schools that I know have large number of buildings and so generating systems might be 10 times what the average household system is. A 30kw system would need a bigger inverter but other component costs should be lower than for home system due to the larger scale.

The potential generation capability might be much higher than 30kw per school but at that level it would be significant saving on electricity expenses and allow schools more flexibility in their budgets.

The barrier would be capex for most. From 2006-2010 Genesis Energy and the government actually had a school programme in place which extended to 42 schools who all have 2kw systems still in place.

“Providing 42 schools across the North Island with a 2 kilowatt (kW) PV system, at no cost to the schools. The PV system allows these schools to generate a portion of their electricity from the sun, and to teach their students about solar energy, climate change and electricity generation”…
“Genesis Energy has installed 84kW of PV capacity in New Zealand as of the end of 2011…”

What would it take to upgrade those 42 existing schools beyond 2kw systems given that PV costs are down and electricity costs are up?* I don’t know the answer to that but it is an excellent question. I will research but best estimates are up to $30k for a completely new 10kw system so I would guess at something like $50k (for 20kw) for each school assuming the existing panels would be reused. There are also micro-inverter systems which allows panels to be easily added over time.

(From some research it looks like natural system sizes based on current inverters would be up to 10kw or 17kw and inverters can be added at those levels – so 27kw might include 1 x 17kw & 1 x 10 kw inverter.)

Imagine if those 42 schools went to 20kw each that would be an extra 756kw for a total of 840kw. Those numbers could be higher in some schools and lower in others. In Northland for example they have more sunshine hours and proces for electricity are often higher so they can benefit more.

As the parent of a school age child I would guess that parents would also be supportive of such a programme as it would also mean other school fundraising could go further.

Despite this programme having lost its government funding back in 2010 it seems like a number of South Island schools are joining the schoolgen programme. My view is that this would be a great solar project to review and would have real tangible cost benefits to the schools themselves. As schools are at the heart of local communities this will also provide a great example to private home owners.

There are other benefits such as carbon savings. Click on the image below or this link to see view some live stats from the Schoolgen project. As at today Schoolgen programme Total: 402637 kWh | 78.29 tonnes CO2 saved seems quite impressive. Now if instead of 42 x 2kw systems that was 42 x 20kw systems that would be a much more significant impact.

Note: For example if we assumed that the school systems could be scaled up to 20kWh in each case then a simple equation would be to multiply by 10 to get a rough estimate of the volumes. So the scheme has generated 402,637kwh so far. If that was multiplied by 10 then 402,637 becomes 402 mwh which is a significant number. That number is over about 4 years so divide by 4 to get the annual impact which is still very impressive.

From other sources at EECA it seems there were around 3,400 homes using solar water heating which is also a small but important number.

schoolgen-data12mths

By way of comparison Australia has also had a solar PV in schools programme. In Australia 2,870 schools have installed solar panels. In 2012/13 in Au ( works out to be around $30k each school) In NZ indicative prices are that *$30k NZ would get a 10kw system on each roof or $24k in $A…

“Over $24 million will be distributed to 804 Australian schools to install solar power systems and a range of energy efficiency measures as they take action against climate change.”