Special Bd. of Aldermen — 08/06/2019 Page 15
cases because what that does is we are adding significant extra cost to our racking and support systems, which
really must be offset by the additional generation that they provide. So in these power purchase agreement
projects where we do typically have expansive roof or ground spaces, the juice isn’t worth the squeeze.
Alderman Dowd
Ok the other thing that is being discussed in places is having part of the power from the solar panels be able to
charge batteries that can be used especially in the winter when you get some power and they can put it in the
batteries and use it at night for instance. Is that something that you’re involved in?
Mr. Hasselbeck Deeply involved yesterday | was just in Durham with EverSource and UNH talking about their
micro grid initiative. So we are deeply involved in that; we are the largest installer of commercial and residential
battery based systems in New Hampshire and Maine. Right now, today — for these types of projects, that
technology is not cost effective, it actually harms the economics. But what is really great is we are designing all
of our systems to be future compatible with what we call AC Coupled Battery Systems. So your new school in
particular, another 2 years give or take, we are going to see the same downward pressure on battery cost,
manufacturing costs that we’ve seen historically in PV panels. So | could make a convincing argument that
instead of a conventional propane generator for your new school, we should spend that money instead on a
large battery which will provide emergency backup power and also provide additional opportunities for savings
by doing demand response, which the utilities are talking about and we are working on in Massachusetts. So
long story short, yes that’s awesome — not yet, but these systems will be in the future if desired compatible with
the battery.
Alderman Dowd
OK | may have added questions but | will let somebody else ask some.
Mr. Hasselbeck This has been fun for me though.
Alderman O’Brien
Thank you to Mr. Hasselbeck you sparked my interest with the, no pun intended, with the fastening type of
system. Basically what | am concerned about is like you say | want to focus on the ballast system. We do live
in New England and | understand it is the weight of the ballast that holds it to the roof. So what are some of the
engineering, we do get the occasional hurricane, | understand we are not in tornado alley. But then again |
could understand that all bets are off with a tornado, but with the New England Noreaster and everything else
like that how does the ballast system really stand up in this type of weather climate?
Mr. Hasselbeck Yeah really well so we look at you know local snow loads, local wind loads. So the same type
of design criteria that a new building has to be put through, you know with the specific wind loads for this town,
this City, building height is a factor, whether there are parapets or whether it is a flat roof, the proximity of the
solar rays to the edge of the roof. If you saw on our designs, there’s a four foot gap between the edge of the
roof and the beginning of the solar panels, that serves two purposes. One for that maintenance and fire access
if needed; two, it actually significantly reduces the loading on that system. The other thing is that we are not
looking, all these panels are connected in a large horizontal basically. So we get the benefits of this basically
large kind of interconnected entity, instead of just one individual solar panel at a time. So I’d be happy to get
into the weeds on all the calcs that get done to make sure that they don’t blow off, but I’ve never lost one yet
and | sure as heck don’t plan to in downtown Nashua.
